WE REPLACED REDIS WITH MYSQL FOR INVENTORY RESERVATIONS—AND IT SCALED (2026)

Summary from the TLDR Dev newsletter

Shopify transitioned its inventory reservation system from Redis to MySQL to improve reliability and scalability during peak sales periods, particularly on high-traffic days like Black Friday. The change involved adopting MySQL's SKIP LOCKED feature, allowing for more efficient management of inventory reservations and improved ACID compliance while reducing the potential for overselling or underselling products.